The track chassis is very likely the M113A4 MTLV with a 400 or 600 hp diesel. The 15in wide 'band' track was designed for this chassis, and the MTLV has a electric hybrid varient that has been demonstrated. This also appears to be the same chassis
(6 road wheels) as used on the M8 AGS.
Note: An 18in band track has not been developed for the M1/M2 yet.

I was wrong GDLS does not built the MTVL. UDI is the manufacturer. These two companies have teamed up to come up with FCS varients.
In January 2003, the U.S. Army and Defense Advanced Research Projects Agency (DARPA) selected United Defense to team with General Dynamics Land Systems (GDLS) and the Lead Systems Integrator (Boeing/SAIC) in the design of the ground vehicles portion of Future Combat Systems (FCS), a critical component of the Army's planned force transformation. FCS will use significantly enhanced battlefield knowledge to improve the combat power of a network of vehicles, sensors and weapons.
The FCS Lead System Integrator (Boeing/SAIC) formed the Manned Ground Vehicle design team, allowing the two companies to immediately begin design work on the manned ground vehicles in order to support the aggressive timeline to achieve first unit-equipped by 2008.
The companies will focus on assessing the requirements of the eight manned ground vehicle variants, developing preliminary designs for each vehicle, and identifying the components and subsystems that will be common to all. These early designs and technical insights will facilitate a successful milestone review later this spring and the broader industry competition for the systems development and demonstration phase.
United Defense is responsible for developing and building the Infantry Carrier Vehicle, the Future Maintenance & Recovery Vehicle, the Medical Vehicle and the Non-Line-of-Sight Cannon (NLOS-C) and Mortar (NLOS-M).
United Defense is also working directly with the Army on several related technology development efforts in the areas of advanced survivability, hybrid power systems, unmanned vehicles, electrothermal chemical gun propulsion and advanced ballistic composites. United Defense has already built two hybrid electric prototypes for FCS - the FCS-T, a diesel electric with band track and lithium ion batteries (link to the data sheet info) and the FCS-W, a turbine electric 8x8 wheeled vehicle with an advanced structure/armor comprising ceramics, titanium, aluminum-lithium alloy, and polymer composites.